The invention relates to a 1C system and a method for manufacturing semifinished products (prepregs) and components with the 1C system.
Prepregs are semifinished products that are to be processed into various spatial components used in various industrial sectors such as aircraft construction.
Customary duroplastic prepregs are comprised of continuous fibers and an unhardened duroplastic plastic matrix and are primarily used in lightweight construction. The continuous fibers form a reinforcement layer and are added to the prepreg in the form of fabrics, scrims or fibers with a unidirectional arrangement. Glass, carbon, basalt or aramid fibers, as examples, are used in connection with this. Because of their excellent plastic workability, the prepregs can be stored and delivered in a sheet or web-type form (on reels). The prepregs have to be cooled while stored, which is a drawback, to prevent a premature reaction of the resin with the curing agent. Storage over long periods of time can only be enabled in that way. A premature hardening of the prepreg already comes about at room temperature, which is a disadvantage; shaping is made more difficult or impossible because of that.
An epoxy resin composition, comprised of a resin and a curing agent and optionally an accelerator, is usually used as the unhardened duroplastic plastic matrix with which the continuous fibers are impregnated. This matrix simultaneously surrounds and imbues (impregnates) the reinforcement layer.
To create the spatial components, customary prepregs are first put into the desired shape and then hardened at a specific temperature. In so doing, cross-linkage of the duroplastic plastic matrix comes about and therefore a hardening and strengthening of the prepreg.
US 2006/035088 A discloses, as an example, a composition for the pre-impregnation of a reinforcement layer in which precisely specified amounts of resins, amine compounds containing sulfur, and urea and dicyanodiamide compounds are mixed together as latent curing agents in a specified order. The carbon fibers, existing in the form of fabric or slivers, are pre-impregnated with this composition. Final products can be created from that under increased pressure and increased temperature in the end.
CN 1027 02683 discloses a composition made of an epoxy resin and colophonium for creating prepregs. A reinforcement layer is soaked with the above-mention composition and processed into a prepreg in presses via a pressure effect or via heating in autoclaves and subsequent cooling. The prepregs that are pre-impregnated in that way can be stored for around one month at room temperature. After the shaping, the prepregs can be hardened by heating them to 125° C.; the colophonium becomes a cross-linking agent. The relatively short storage period of only one month is a drawback here.
JP H0820708 A discloses a method for creating prepregs that are pre-impregnated with a composition made up of epoxy resin and a micro-encapsulated amine adduct as the cross-linking agent. The prepregs are hardened at temperatures over 80° C. by the release of the cross-linking agent.
JP H11171980 A discloses a composition made up of an epoxy resin, a cross-linking agent selected from polyamine, polyphenol or acid anhydride and an organic compound containing phosphorus and boron that is formulated as a solution. Prepregs soaked with that can be easily shaped and are more stable when stored at room temperature.